1. Technical Field
The present invention relates to a clock supplying apparatus for a synchronous transmission system, and more particularly to an apparatus for supplying a clock to a line with a reduced time delay in a multiline synchronous transmission system.
2. Related Art
In a synchronous radio transmission system, a clock is one of important elements determining the performance of the system. Especially, in a general multiline system, clocks are generated with respect to respective lines due to a delay and skew of a supplied clock, and the generated clock is used only at a corresponding line. Clocks used in the radio transmission system are widely divided into a system clock for transmitting data, a clock reproduced from data which is received from the other station, and a line clock for generating a reference clock from the reproduced clock by using a PLL (phase locked loop).
The synchronous radio transmission system includes, with respect to each line, a frequency synthesizer for synchronizing a frequency and a PLL circuit for generating a reference signal from a reproduced signal. That is, each line requires at least two clock generators. Therefore, it is not easy to synchronize a clock for each line. Moreover, the cost of production rises and a product of a compact construction is not obtained. Further, since a synchronous system is used, it is difficult to maintain compatibility between lines in the multiline system.
I have found that problems with transmission systems can be extremely inconvenient. Efforts have been made to improve transmission systems.
Exemplars of recent efforts in the art include U.S. Pat. No. 5,610,907 for ULTRAFAST TIME HOPPING CDMA-RF COMMUNICATIONS: CODE-AS-CARRIER, MULTICHANNEL OPERATION, HIGH DATA RATE OPERATION AND DATA RATE ON DEMAND issued to Barrett, U.S. Pat. No. 5,357,542 for REPEATER STATION WHEREIN INPUT FRAME DATA ARE ACCESSIBLE issued to Suzuki, U.S. Pat. No. 4,984,247 for DIGITAL RADIO TRANSMISSION SYSTEM FOR A CELLULAR NETWORK, USING THE SPREAD SPECTRUM METHOD issued to Kaufmann, U.S. Pat. No. 4,972,410 for METHOD AND APPARATUS FOR CONTROLLING SIGNAL COHERENCY IN SIMULCAST SYSTEMS issued to Cohen et al., U.S. Pat. No. 4,481,640 for SPREAD SPECTRUM MODEM issued to Chow et al., and U.S. Pat. No. 35,209 for SPREAD SPECTRUM COMMUNICATIONS SYSTEM issued to Partyka et al.
While these recent efforts provide advantages, I note that they fail to adequately provide a clock supplying apparatus for a multiline transmission system.
It is therefore an object of the present invention to provide a clock supplying apparatus which can minimize a delay and skew of a clock by generating a stabilized clock using a digital technology.
It is another object of the present invention to provide an apparatus for supplying the same clock generated from one clock generator to an entire system.
To achieve these and other objects, the present invention provides an apparatus for supplying a clock in a multiline radio transmission system, including a clock generator for generating a clock from a reference signal, a clock branching module for receiving the clock generated from the clock generator and branching the clock, at least one clock patching module for receiving the branched clock from the clock branching module and patching the clock, and a clock distribution module for receiving the patched clock from the clock patching module and distributing the clock to each unit for receiving a clock of the multiline radio transmission system.
To achieve these and other objects in accordance with the principles of the present invention, as embodied and broadly described, the present invention provides an apparatus supplying a clock signal, comprising: a clock generator generating a first clock signal in response to a reference signal; a clock branching unit receiving said first clock signal and outputting a plurality of second clock signals in response to said first clock signal, said plurality of second clock signals including an alpha clock signal and a beta clock signal; at least one first clock patching unit receiving said alpha clock signal from said clock branching unit and outputting a first patched clock signal corresponding to said alpha clock signal; a multiline transmission system transmitting data on a plurality of first lines, said system comprising a plurality of first monitoring units monitoring a status of said plurality of first lines; and a first clock distribution unit receiving said first patched clock signal from said at least one first clock patching unit and distributing said first patched clock signal to each one of said plurality of first monitoring units of said multiline transmission system.
To achieve these and other objects in accordance with the principles of the present invention, as embodied and broadly described, the present invention provides an apparatus supplying a clock signal, comprising: a clock generator generating a first clock signal; a transmission system transmitting data on a plurality of first lines, said system comprising a plurality of first monitoring units monitoring a status of said plurality of first lines; and a first clock distribution unit receiving a first patched clock signal corresponding to said first clock signal, said first clock distribution unit distributing said first patched clock signal to each one of said plurality of first monitoring units of said transmission system.
To achieve these and other objects in accordance with the principles of the present invention, as embodied and broadly described, the present invention provides an apparatus supplying a clock signal, comprising: a clock generator generating a first clock signal; a transmission system transmitting data on a plurality of first lines; and a first clock distribution unit receiving a first patched clock signal corresponding to said first clock signal, said first clock distribution unit distributing said first patched clock signal to each one of said plurality of first lines of said transmission system.
The present invention is more specifically described in the following paragraphs by reference to the drawings attached only by way of example. Other advantages and features will become apparent from the following description and from the claims.